Standard broadband connection delivered over a telephone line. Asynchronous Digital Subscriber Line. Asynchronous refers to the difference in upload and download speeds i.e. download is normally faster than upload.

The address resolution protocol (arp) is a protocol used by the Internet Protocol (IP), specifically IPv4, to map IP network addresses to the hardware (MAC) addresses. ARP tables list the IP addresses assigned to devices and the corresponding MAC address of each device. The term address resolution refers to the process of finding an address of a computer in a network. The address is "resolved" using a protocol in which a piece of information is sent by a client process executing on the local computer to a server process executing on a remote computer

Eight bits. A bit (Binary digIT) is a single unit of data having two possible states: 1 or 0. A byte is a collection of eight bits to produce 2^8 possible states (256) and faster communication. Examples of larger collections of bytes are kilobytes (kB - notionally 1,000 bytes (8,000 bits)), megabytes (MB, one million) and gigabytes (GB, one billion). Note that bytes are represented by a capital B, while bits are represented by a lower-case b. It is convention for amounts of data to be referred to in bytes e.g. 2MB; while data transfer speeds shown in bits e.g. 16Mb (or 16Mbps (per second)).

Chromecast is a line of digital media players developed by Google. The devices, designed as small dongles, enable users with a mobile device or personal computer to initiate and control playback of Internet-streamed audio/visual content on a high-definition television or home audio system through mobile and web apps that support the Google Cast technology. Alternatively, content can be mirrored from the Google Chrome web browser running on a personal computer, as well as from the screen of some Android devices.

Calling Line Identity. This is the name or number that is displayed on a receiver’s telephone handset when taking a call.

Communications room. A room providing a safe environment for technical equipment (IT, telephony etc). The advantages of a comms room are: co-location of many interconnecting devices and systems; all can be air-conditioned to prevent failure and to extend the life of the equipment; the room can be locked to prevent tampering. There can be multiple comms rooms at any particular location. Also known as apps (apparatus) room and equipment room.

Direct Dialling Inward. DID. The actual telephone number associated with an extension or handset.

Dynamic Host Configuration Protocol; sometimes Dynamic Host Control Protocol. A system that automatically distributes IP addresses to devices on a network.

Direct Inward Dialling; also DDI. The actual telephone number associated with an extension or handset.

Do Not Disturb. A feature on a telephone handset that effectively puts it into standby.

Domain Name Service. A system that associates URLs with IP addresses e.g. it is convenient for users to type bbc.co.uk to access the BBC website, but the web browser needs to know that the address might be 212.58.244.23. DNS provides the browser with this association.

DTMF (Dual-tone multi-frequency signalling) is an in-band telecommunication signalling system using the voice-frequency band over telephone lines between telephone equipment and other communications devices and switching centres. The Touch-Tone system (USA) using a telephone keypad gradually replaced the use of rotary dial and has become the industry standard for landline and mobile service. Other multi-frequency systems are used for internal signalling within the telephone network.

In relation to computer networks, dynamic can refer to IP addresses that are assigned to a device automatically (DHCP) and that can change after a period of time - from the next boot to never. It can also refer to ’dynamic routing’ - a general term for a number of protocols that enable routers to learn for themselves the best route for data at any one time. The alternatives are static IP addressing and static routing.

In computing, a firewall is a network security system that monitors and controls the incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted, secure internal network and another outside network, such as the Internet, that is assumed not to be secure or trusted. Firewalls are often categorised as either network firewalls or host-based firewalls. Network firewalls filter traffic between two or more networks; they are either software appliances running on general purpose hardware, or hardware-based firewall computer appliances. Host-based firewalls provide a layer of software on one host that controls network traffic in and out of that single machine.

The File Transfer Protocol (FTP) is a standard network protocol used for the transfer of computer files between a client and server on a computer network.

Graphical User Interface. The graphics that enable us to visually interact with a computer i.e. those on a computer or smartphone screen. The term is often used in relation to the design of a particular program’s user interface i.e. pertaining to its aesthetic qualities and/or practical effectiveness..

HDMI (High-Definition Multimedia Interface) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from a HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video projector, digital television, or digital audio device.[4] HDMI is a digital replacement for analogue video standards.

In telephony, line hunting (or hunt group) is the method of distributing phone calls from a single telephone number to a group of several phone lines. Specifically, it refers to the process or algorithm used to select which line will receive the call. Hunt groups are supported by some PBX phone systems. Also, some phone companies will provide this feature for a small fee (see also: Centrex). In the tariffs of some telephone companies, one may obtain hunting for free, but forward on busy is a charged service.

The Internet Protocol (IP) is the principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet. IP has the task of delivering packets from the source host to the destination host solely based on the IP addresses in the packet headers. For this purpose, IP defines packet structures that encapsulate the data to be delivered. It also defines addressing methods that are used to label the datagram with source and destination information. Historically, IP was the connectionless datagram service in the original Transmission Control Program introduced by Vint Cerf and Bob Kahn in 1974; the other being the connection-oriented Transmission Control Protocol (TCP). The Internet protocol suite is therefore often referred to as TCP/IP.

Integrated Services Digital Network. A type of fast digital business grade telephone line. Early digital data technology superseded by ADSL due to cost. Still used by broadcasters to some extent, but dying out fast.

IVR (Interactive voice response) is a technology that allows a computer to interact with humans through the use of voice and DTMF tones input via keypad.

A manufacturer of telephony hardware.

Local Area Network. A computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building and has its network equipment and interconnects locally managed. By contrast, a wide area network (WAN) not only covers a larger geographic distance, but also generally involves leased telecommunication circuits or Internet links. An even greater contrast is the Internet, which is a system of globally connected business and personal computers.

Premium internet connectivity product, delivered over fibre normally, which is dedicated and provides uncontended, symmetrical speeds. Links internet provider with the customer’s premises

NTP (Network Time Protocol) is a networking protocol for clock synchronisation between computer systems over packet-switched, variable-latency data networks i.e. the internet.

Or passthrough. A network router provides a gateway between networks and can provide services such as a firewall. Making a router transparent between two networks so that data effectively passes unchecked is known as passthru mode.

A row, or rows, of sockets that allows devices to be interconnected with the use of patch leads (a lead with the same connector at each end). Patch panels can be used to bring all sockets together into one place - often at the front of a bay, rather than at the back of all the devices. This then allows a system to be replugged differently very easily. Also know as a jackfield (JF) in the UK, especially broadcasting.

Private Branch Exchange: a telephone exchange or switching system that serves a private organisation. Old style analogue or digital systems using standard telephone lines tend to be large units installed onsite e.g. Avaya systems. Cloudcalling is a hosted IP PBX hosted offsite.

Pulse Code Modulation. A form of sampling normally taken to infer high quality audio, as in WAV files.

Power over Ethernet - a technology that lets network cables carry electrical power, meaning the receiving device does not need a separate power supply.

Port has several meanings in IT:  Switch port – physical socket on a switch or other device, for instance a MESH switch (Switch 1 Port 5);  Wall port / floor port – physical socket taking a connection (usually) somewhere else in the building.  Internet port – a virtual (non-physical) port. Different types of communication on the internet use different ports. The number is appended to the end of an IP address. A common example is basic web page traffic which is port 80. Using the block of flats analogy above, the port number might be a particular person in one of the flats. Firewalls work by blocking all traffic in certain directions, and port forwards are specific ports that are not blocked. This can get quite complicated and it is best to speak to Stickman if you have a customer asking many questions about internet ports.  One important point to note is that the MESH in-built firewall only ever blocks incoming traffic, never outgoing, so all ports are open outgoing. When a client is on Passthru mode the MESH firewall is disabled, so all ports are open in both directions.  Telephone number porting – A process of moving a telephone number from one provider to another.

Plain Old Telephone System – standard analogue telephone service. Basic home landline.

A software program responsible for managing all print jobs currently being sent to the computer printer or print server. The print spooler program may allow a user to delete a print job being processed or otherwise manage the print jobs currently waiting to be printed.

A software program responsible for managing all print jobs currently being sent to the computer printer or print server. The print spooler program may allow a user to delete a print job being processed or otherwise manage the print jobs currently waiting to be printed.

In the UK, ’program’ relates to computer software or applications. All other uses of the word i.e. non-computing, are spelled ’programme’ e.g. TV programmes or training programmes. The USA uses ’program’ in all cases.

Public Switched Telephone Network – Standard telephone line connected to the public telephone network.

Power Supply Unit. Any type of device supplying power to another device; usually converting mains electricity to a lower DC voltage. This could be an internal unit, or something external e.g. a ’wall-wart’.

Port VLAN ID. A method of tagging data packets with the VLAN they belong to.

Remote Desktop Protocol (RDP) is a proprietary protocol developed by Microsoft, which provides a user with a graphical interface to connect to another computer over a network connection. The user employs RDP client software for this purpose, while the other computer must run RDP server software.

A server is usually a powerful computer that provides specific services such as DHCP or file delivery to many other computers and users.

Simple Mail Transfer Protocol (SMTP) is an Internet standard for electronic mail (email) transmission. First defined by RFC 821 in 1982, it was last updated in 2008 with Extended SMTP additions by RFC 5321, which is the protocol in widespread use today. Although electronic mail servers and other mail transfer agents use SMTP to send and receive mail messages, user-level client mail applications typically use SMTP only for sending messages to a mail server for relaying. For retrieving messages, client applications usually use either IMAP or POP3. SMTP communication between mail servers uses TCP port 25. Mail clients on the other hand, often submit the outgoing emails to a mail server on port 587.

A manufacturer of telephone receiving equipment.

Software that emulates the functionality of a physical telephone; such as Voice Operator Panel for Windows, or a large range of apps for mobile telephones.

Service Set Identifier. The name of a wireless network device. For example, the names that appear in a list of available WiFi devices are all SSIDs.

In relation to computer networks, static can refer to IP addresses that are manually assigned to a device and that do not change; or to ’static routing’ - the method of configuring routers so that they use a lookup table to pass data through network nodes. The alternatives are dynamic IP addressing (DHCP) and dynamic routing, for which there are a number of protocols.

Officially known as the notification area, the system tray (Systray) is also sometimes referred to as the shell notification area or taskbar status area. It is part of the Windows 95, 98, NT, ME, 2000, XP, Vista, 7, and 8 operating systems. This section of Windows displays small icons enabling a user to know what is currently loaded in the computer’s memory. The Systray is located at the bottom right-hand-side of the screen and is next to the current time. The systray can now be extended by clicking the up arrow within it.

The Transmission Control Protocol (TCP) is one of the main protocols of the Internet protocol suite. It originated in the initial network implementation in which it complemented the Internet Protocol (IP). Therefore, the entire suite is commonly referred to as TCP/IP. TCP provides reliable, ordered, and error-checked delivery of a stream of octets between applications running on hosts communicating by an IP network. Major Internet applications such as the World Wide Web, email, remote administration, and file transfer rely on TCP. Applications that do not require reliable data stream service may use the User Datagram Protocol (UDP), which provides a connectionless datagram service that emphasizes reduced latency over reliability.

Three-letter abbreviation, or three-letter acronym. There are many of these: BBC, TRS, PSU and ATM for example. TLA is itself a TLA.

In electronic communication, the User Datagram Protocol (UDP) is one of the core members of the Internet protocol suite. The protocol was designed by David P. Reed in 1980 and formally defined in RFC 768. With UDP, computer applications can send messages, in this case referred to as datagrams, to other hosts on an Internet Protocol (IP) network. Prior communications are not required in order to set up transmission channels or data paths. UDP uses a simple connectionless transmission model with a minimum of protocol mechanism. UDP provides checksums for data integrity, and port numbers for addressing different functions at the source and destination of the datagram. It has no handshaking dialogues, and thus exposes the user’s program to any unreliability of the underlying network: there is no guarantee of delivery, ordering, or duplicate protection. If error-correction facilities are needed at the network interface level, an application may use the Transmission Control Protocol (TCP) or Stream Control Transmission Protocol (SCTP) which are designed for this purpose. UDP is suitable for purposes where error checking and correction are either not necessary or are performed in the application; UDP avoids the overhead of such processing at the level of the network interface. Time-sensitive applications often use UDP because dropping packets is preferable to waiting for delayed packets, which may not be an option in a real-time system.

USB, short for Universal Serial Bus, is an industry standard that defines cables, connectors and communications protocols for connection, communication, and power supply between computers and electronic devices.[4] USB was designed to standardise the connection of computer peripherals (including keyboards, pointing devices, digital cameras, printers, portable media players, disk drives and network adaptors) to personal computers, both to communicate and to supply electric power. It has largely replaced a variety of earlier interfaces, such as serial ports and parallel ports, as well as separate power chargers for portable devices - and has become commonplace on a wide range of devices.

Voice over Internet Protocol (Voice over IP, VoIP and IP telephony) is a methodology and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet.

Voice Operator Panel. A software application for managing telephone calls on Windows computers.

Virtual Private Network – a means of connecting to a remote network through a public IP address. The equipment exchanges passwords to encrypt the data travelling between each other.

Wide Area Network. A wide area network covers a larger geographic distance and generally involves leased telecommunication circuits or internet links. An even greater contrast is the Internet, which is a system of globally connected business and personal computers. By contrast, a local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building and has its network equipment and interconnects locally managed.

Wireless Access Point. A networking hardware device that allows a WiFi compliant device to connect to a wired network. The WAP usually connects to a router (via a wired network) as a standalone device, but it can also be an integral component of the router itself. A WAP is differentiated from a hotspot, which is the physical location where WiFi access to a WLAN is available.

The short name or file extension of a wave file, sometimes wav or .wav. These are PCM audio files, meaning they are linear and have had no data compression applied (unless converted from a compressed format).

Wireless Local Area Network. A wireless computer network that links two or more devices using a wireless distribution method (often spread-spectrum or OFDM radio) within a limited area such as a home, school, computer laboratory, or office building. This gives users the ability to move around within a local coverage area and yet still be connected to the network. A WLAN can also provide a connection to the wider Internet.

In computing, Extensible Markup Language (XML) is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. The design goals of XML emphasize simplicity, generality, and usability across the Internet. It is a textual data format with strong support via Unicode for different human languages. Although the design of XML focuses on documents, the language is widely used for the representation of arbitrary data structures such as those used in web services.